2002

Habilitation at Department of Educational Science and Psychology, Freie Universität Berlin

1997

Ph.D. at Department of Educational Science and Psychology, Freie Universität Berlin

1987

Studies of Physics at Institut National des Sciences Appliquées, Lyon (France), Grant by DAAD

1985-1991

Studies of Mathematics and Physics (First State Examination for Teaching in Secondary Schools), Technische Universität Berlin

2007 - 2010

Invited Guest Professor at Department of Educational Science and Psychology, Freie Universität Berlin

2007

Invited Guest Professor at Centro de Estudios de Postgrado y de Investigación en Educación Superior, Universidad Mayor de San Andrés, La Paz (Bolivia)

2004 - 2010

University Professor for Mathematics Education, Department of Educational Science, Universität Hamburg

2004

Invited Guest Professor at Department of Mathematics, Johann Wolfgang Goethe-Universität Frankfurt

2001 - 2002

Guest Professor at Department of Educational Science, Universidad Metropolitana de Ciencias de la Educación, Santiago de Chile

2001

Feodor-Lynen-Scholarship for Research in Chile by Alexander-von-Humboldt-Foundation

1998 - 2004

Assistant Professor (C1) at Department of Educational Science and Psychology, Freie Universität Berlin

1993 - 1998

Scientific Collaborator (BAT IIa) at Department of Educational Science and Psychology, Freie Universität Berlin

1991 - 1993

Teaching Practice in Secondary Mathematics and Physics (Second State Examination for Teaching in Secondary Schools), Berlin